Process for manufacturing polyurethane foams

Abstract

The present invention is directed to flexible polyurethane foams useful as seat cushioning material for vehicles, aircraft, furniture and the like. The polyurethane foams are characterized by improved wet compression set properties, improved firmness, resilience and elongation. The foams are made by a process which comprises reacting a polyol having a hydroxyl equivalent of from 800-10,000, a glycerin derivative having oxyethylene groups thereon but characterized by having a significant number of unreacted secondary hydroxyl groups of glycerin, (c) water and (d) an organic polyisocyanate.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. A process for manufacturing of a polyurethane foam comprising reacting (a) a polyol having a hydroxyl equivalent of from 800 to 10,000,   (b1) a first glycerin derivative of the formula ##STR5##  where n and m are zero or an integer such that the sum of n and m is of from 1 to 8, or   (b2) a mixture of said first glycerin derivative and a second glycerin derivative of the formula ##STR6##  where p and r are zero or an integer, q is an integer of 1 or more such that the sum of p, q and r is of from 1 to 8, and   (c) water; with an organic polyisocyanate in the presence of a catalyst.     
     
     
       2. The process according to claim 1, wherein the polyol is a polyether polyol, a polymer polyol or a combination thereof. 
     
     
       3. The process according to claim 1, wherein the polyol has a hydroxyl equivalent of from 1,500 to 3,000. 
     
     
       4. The process according to claim 1, wherein the polyol is a polyol or polyol mixture having an average number of hydroxyl group of from 2.5 to 5. 
     
     
       5. The process according to claim 4, wherein the polyol is a polyol or polyol mixture having an average number of hydroxyl group of from 3 to 4. 
     
     
       6. The process according to claim 1, wherein the sum of n and m ranges from 2 to 4. 
     
     
       7. The process according to claim 1, comprising of from 1 to 5% by weight based on the polyol of said first glycerin derivative. 
     
     
       8. The process according to claim 1, wherein said polyisocyanate is tolylene diisocyanate or a mixture of at least 70% by weight of tolylene diisocyanate and a modified or crude diphenyl methane diisocyanate. 
     
     
       9. The process according to claim 1, wherein said catalyst is a tertiary amine, a metal carboxylate or an organo-tin or antimony compound. 
     
     
       10. The process according to claim 1, comprising of from 2.5 to 8% by weight based on the polyol of water. 
     
     
       11. A process according to claim 1, wherein said polyurethane foam has a density of up to 45 kg/m 3 . 
     
     
       12. The process according to claim 1, wherein said mixture of (b2) comprises at least 6% based on total number of hydroxyl groups of a secondary hydroxyl group originated from glycerin. 
     
     
       13. The process according to claim 1, wherein said mixture of (b2) comprises not less than 10% based on total number of hydroxyl groups of a secondary hydroxyl group originated from glycerin. 
     
     
       14. The process according to claim 1, comprising of from 1.5 to 7% by weight based on the polyol of said mixture of (b2). 
     
     
       15. The process according to claim 12, wherein the polyisocyanate is tolylene diisocyanate or a mixture of at least 70% by weight of tolylene diisocyanate and a modified or crude diphenyl methane diisocyanate. 
     
     
       16. The process according to claim 12, wherein the catalyst is a tertiary amine, a metal carboxylate or an organo-tin or antimony compound. 
     
     
       17. The process according to claim 12, comprising of from 2.5 to 8% by weight based on the polyol of water. 
     
     
       18. The process according to claim 12, wherein the polyurethane foam has a density of up to 45 kg/m 3 . 
     
     
       19. The process of claim 1, wherein said first glycerin derivative (b1) is a compound made by reacting 2 moles of ethylene oxide with 1 mole of glycerin and contains 50 mole % of glycerin derivatives having the secondary hydroxyl group of glycerin. 
     
     
       20. The process of claim 1, wherein said first glycerin derivative (b1) is a compound made by reacting 3 moles of ethylene oxide with 1 mole of glycerin and which contains 40 mole % of glycerin derivatives having the secondary hydroxyl group of glycerin. 
     
     
       21. The process of claim 1, wherein said glycerin derivative (b1) is 3-hydroxydiethoxy-1,2-propanediol. 
     
     
       22. The process of claim 1, wherein said second glycerin derivative is present in a proportion such that the number of secondary hydroxyl groups at position 2 of glycerin, is at least 6%, and not less than 10% based on the total number of hydroxyl groups in the mixture of the first and second derivatives.